如果列表包含相同的元素，则在嵌套列表中合并列表? [英] Combining lists within a nested list, if lists contain the same element?

问题描述

我有一个嵌套列表，其结构与此类似，只是它的长度明显更长:

I have nested list that has a structure similar to this, except it's obviously much longer:

mylist = [ ["Bob", "12-01 2:30"], ["Sal", "12-01 5:23"], ["Jill", "12-02 1:28"] ]

我的目标是创建另一个嵌套列表，以组合所有具有相同日期的元素.因此，需要以下输出:

My goal is to create another nested lists that combines all elements that have the same date. So, the following output is desired:

newlist = [  [["Bob", "12-01 2:30"], ["Sal", "12-01 5:23"]], [["Jill", "12-02 1:28"]]  ]

上面，所有日期为12-01的项目(无论时间如何)都被合并，而12-02的所有元素都被合并.

Above, all items with the date 12-01, regardless of time, are combined, and all elements of 12-02 are combined.

在过去的1个小时里，我一直在认真研究如何执行此操作，但是找不到任何东西.此外，我是编程的初学者，所以我不够熟练，无法尝试创建自己的解决方案.因此，请不要以为我没有尝试进行研究或亲自尝试解决此问题.我将在下面添加一些链接作为我的研究示例:

I've sincerely been researching how to do this for the past 1 hour and can't find anything. Furthermore, I'm a beginner at programming, so I'm not skilled enough to try to create my own solution. So, please don't think that I haven't attempted to do research or put any effort into trying this problem myself. I'll add a few links as examples of my research below:

收集每对元素从列表中转换为Python中的元组

创建条件为true时具有相邻列表元素的元组列表

如何在Python中连接两个列表?

串联两个列表没有嵌套for循环的Python中明智的Strings元素

根据中的匹配日期将两个列表压缩在一起字符串

如何将列表合并到元组列表中? /a>

How to merge lists into a list of tuples?

推荐答案

在日期时间之前使用dict或orderdict(如果排序很重要)组数据.

Use dict or orderdict(if the sort is important) group data by the date time .

from collections import defaultdict # use defaultdict like {}.setdefault(), it's very facility

mylist = [["Bob", "12-01 2:30"], ["Sal", "12-01 5:23"], ["Jill", "12-02 1:28"]]
record_dict = defaultdict(list)
# then iter the list group all date time.

for data in mylist:
    _, time = data
    date_time, _ = time.split(" ")
    record_dict[date_time].append(data)

res_list = list(record_dict.values())
print(res_list)

输出:
[[['Bob', '12-01 2:30'], ['Sal', '12-01 5:23']], [['Jill', '12-02 1:28']]]

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